Last Updated on November 28, 2023 by Ankit Kochar
Within SQL, character strings find storage through the CHAR and VARCHAR data types. VARCHAR, a variable-length character string data type, allocates memory according to the length of the string, utilizing only what is necessary. In contrast, CHAR represents a fixed-length character string data type, specifying and reserving a set amount of memory for each individual value.
What is Char Datatype?
In SQL, the CHAR datatype is utilized to store character strings of a defined length. This datatype permits the storage of character data with a predetermined size; for instance, a CHAR(10) column accommodates strings precisely 10 characters in length. The content stored in a CHAR column consistently maintains a fixed length, achieved by adding spaces to strings shorter than the specified length to meet the required size.
When you wish to impose a particular column length, such as when you want to store a code, a product identifier, or a phone number, the CHAR datatype can be helpful. It may be quicker to retrieve CHAR data than variable-length data because it is stored in a fixed-length format.
However, it is crucial to remember that if the data saved is shorter than the allowed length, utilising CHAR columns may result in wasted space.
Example of Char Datatype
In this example we create a table with attributes Name and Gender with Varchar and Char data types respectively
CREATE TABLE Student(Name VARCHAR(30), Gender CHAR(6)); INSERT into Student VALUES('Mohit', 'Male'); INSERT into Student VALUES('Anjali', 'Female'); SELECT LENGTH(Gender) FROM Student;
Length(Gender) 6 6
Explanation of the above example
If we observe on output screen the length of Gender is fixed which is 6, this shows that length of Char datatype string are fix, here male string has 4 characters but still it’s showing 6 because remaining spaces are added
What is Varchar Datatype?
Within SQL, the VARCHAR data type is utilized to store character strings that encompass alphanumeric data of diverse lengths. Tailored for text data storage, its definition allows the establishment of a maximum length; for instance, specifying VARCHAR(50) indicates that the text string can extend up to 50 characters. The key advantage of selecting VARCHAR over fixed-length data types such as CHAR lies in its efficient use of storage, as it occupies only the necessary space based on the actual length of the stored data.
Example of Varchar Datatype
Let’s discuss varchar data type examples. Here I also took the same table just to check the length of gender attributes.
CREATE TABLE Student(Name VARCHAR(20), Gender CHAR(6)); INSERT into Student VALUES('Mohit', 'Male'); INSERT into Student VALUES('Anjali', 'Female'); SELECT LENGTH(Name) FROM Student;
Length(Name) 5 6
Explanation of the above code
This is the key distinction between the char and varchar data types since we have a variable result in this example that displays the actual length of the string.
Differentiate between Char and Varchar Datatypes
Now we differentiate between char and varchar data types:
|Varchar fields do not have a fixed length||Char fields have a fixed length specified when creating the field|
|Flexibility: varchar is more flexible than char||Char is less flexible than Varchar|
|Varchar uses less space||Char uses a fixed amount of space regardless of the length of the string|
|Sorting is slow in Varchar as compare to char||Char fields are faster to sort|
|Varchar is more commonly used in modern databases and programming languages.||Char fields are more compatible with older database systems and are easier to work with in some programming languages|
Use of Char Datatype
As we know CHAR data type in SQL is a fixed-length character string data type used to store alphanumeric values of a specified length. a
- Storing values with a fixed length, such as postal codes, product codes, etc.
- Storing values with a known length that will not change, such as gender or marital status.
- Padding values to a fixed length to improve the appearance of reports.
It’s important to note that using the CHAR data type will always result in a fixed-length string and any unused space will be filled with padding characters. This can result in wasted storage space, so it’s important to choose the appropriate data type based on the specific requirements of your application.
Use of Varchar Datatype
As we know VARCHAR data type is used to store variable-length alphanumeric values, allowing for storage of only the amount of data needed to represent the value.
- Character data storage: VARCHAR is used to store character data such as names, addresses, and other textual information.
- Dynamic data storage: VARCHAR is suitable for storing dynamic data that may vary in length, such as product descriptions, comments, and other user-generated content.
- Reduced storage space: VARCHAR uses less storage space than CHAR when storing values that are shorter than the maximum length specified, as it does not require padding.
- Improved data retrieval performance: VARCHAR can lead to improved performance when retrieving data, as it does not waste storage space and reduces the amount of data that needs to be read from disk. However, it’s important to consider the trade-off between storage space and the increased processing time required to manage variable-length data
Char vs Varchar Mysql
Strings of a fixed length are stored using the fixed-length data type CHAR. To make up the difference if a string is shorter than the desired length, spaces are inserted. If a column is defined as CHAR(10), for instance, it will hold strings that are exactly 10 characters long, including any following spaces.
On the other hand, strings of different lengths can be stored in VARCHAR, a variable-length data type. Only the precise amount of space required is used because the length of the string is recorded alongside the string itself. If a column is defined as VARCHAR(10), for instance, it can store strings with up to 10 characters.
In general, it is advised to utilize VARCHAR rather than CHAR because it is more adaptable and storage-efficient.
In conclusion, understanding the differences between the CHAR and VARCHAR data types is crucial for database developers and administrators. Both data types have their own unique characteristics and usage scenarios.
CHAR is a fixed-length data type that stores a specific number of characters, regardless of the actual data length. It is suitable for storing data with a consistent length, such as codes or identifiers. While CHAR requires a fixed amount of storage space, it can provide faster data retrieval and indexing.
On the other hand, VARCHAR is a variable-length data type that stores data based on its actual length. It is more flexible and efficient for storing variable-length data, such as names or descriptions. Unlike CHAR, VARCHAR uses only the necessary amount of storage space, which can save storage resources.
Frequently Asked Questions(FAQ) related to Differentiate between Char and Varchar Data Type:
Here are some frequently asked questions (FAQs) related to differentiating between CHAR and VARCHAR data types in SQL:
1. What is the primary distinction between CHAR and VARCHAR data types in SQL?
The primary difference lies in their treatment of storage space. CHAR is a fixed-length data type, while VARCHAR is variable-length.
2. How does the CHAR data type store data compared to VARCHAR?
CHAR allocates a fixed amount of storage space for each value, padding with spaces if the actual data is shorter than the specified length. VARCHAR, on the other hand, dynamically adjusts the storage space based on the actual length of the data.
3. When would I prefer to use CHAR over VARCHAR?
CHAR is typically preferred when the data values are consistently of a fixed length, and you want to ensure a constant length for each stored value.
4. In what scenarios is VARCHAR more advantageous?
VARCHAR is more suitable when dealing with variable-length data, where the length of the values may vary, and you want to optimize storage by only using space proportional to the actual data length.
5. How is memory utilization different between CHAR and VARCHAR?
CHAR uses a fixed amount of storage for each value, potentially leading to wasted space. VARCHAR dynamically adjusts storage, reducing wasted space and offering more efficient memory utilization.